1. Field of the Invention
The present invention relates to health care intensive care/specialty mattresses, and in particular to such mattresses having a removable heel pillow for use in the prevention and treatment of pressure sores and other tissue damage aggravated by pressure or resulting from abrasion and/or shearing.
2. Description of the Related Art
It is well known that bedridden patients are often subject to pressure sores due to the patient's weight causing the skin to be pressed between the patient's bone structure and the underlying surface. For example when an individual lies in a given position for an extended period of time, protrusions in the skeletal structure, such as the heels, cause the soft tissue covering the heel bone to be squeezed against the underlying supporting mattress. As soft tissue is squeezed, the blood flow in the area is altered, making that tissue especially susceptible to pressure sores. Pressure sores are particularly prevalent in the vicinity of bony protrusions, and can occur within as short a period of time as 2-4 hours.
Pressure sores are caused by the reduction or lack of blood flow to skin and muscle tissue. The deprived cells quickly die and sores form. These sores often become open wounds which can spread throughout the body's soft tissue and finally expose the bone mass itself. Predisposing conditions which contribute to the formation of pressure sores include circulatory disease and the exposure of tissue to extreme temperatures, as well as shearing, i.e. internal friction, which can stretch and close capillary vessels. The major cause of pressure sores, however is pressure.
In the past a variety of mattresses have been devised to eliminate or reduce pressure creating surfaces of mattresses. In particular, consideration has been given to providing mattresses with cut-out sections such as in U.S. Pat. No. 2,810,920 issued to Carruth on Oct. 29, 1957; U.S. Pat. No. 4,536,906 issued to Varndell et al. on Aug. 27, 1985; U.S. Pat. No. 4,628,557 issued to Murphy on Dec. 16, 1986; U.S. Pat. No. 4,706,313 issued to Murphy on Nov. 17, 1987; and U.K. Patent No. 1,518,845 issued to Hargest on Jul. 26, 1978. In addition, a foam mattress having two layers and a removable antimicrobial, moisture impervious outer cover is disclosed in U.S. Pat. No. 5,136,741, issued to Balonick et al. on Aug. 11, 1992.
The Carruth patent discloses a mattress with a removable plug in a recessed section of the mattress. The plug is used to fill the recess and is made from the same material as the mattress body in order to provide continuity with the mattress body when the plug is in place. The recessed section allows a person's face to be inserted in the recessed section when the person is lying face down on the mattress.
The Varndell et al. patent discloses a mattress having a removable head supporting perforated insert. The insert is made of foam and has the same thickness as the rest of the mattress body. The insert serves to reduce the risk of suffocation when a patient is lying face down on the mattress.
The Murphy ('557) patent discloses a mattress with removable foam inserts and having a cut-out portion in the mattress that goes all the way through the mattress, with the cover of the mattress forming the bottom of the cut-out.
The Murphy ('313) patent discloses a mattress having a plurality of recesses in the top surface of the mattress with a plurality of foam inserts to be placed in the recesses. There must be at least one opening in the mattress and the cover over the opening is required to have a specific configuration.
The British patent issued to Hargest discloses a single layer mattress with a cavity, into which removable inserts of variable densities differing from the density of the material used in the rest of the mattress are placed. The inserts are made of a foam product that is cut so that a plurality of two-inch squares of foam product, with one-inch space in between, lies on one side of the insert.
While the mattresses of the past have been relatively successful in reducing the pressure creating surfaces of a mattress, they have also encountered several disadvantages and difficulties. For example, these mattresses required a patient's heels or other areas of bony protrusion to be positioned directly over only one relatively small spot in the mattress where the insert was located. Also, since mattresses of the past utilized inserts of varying density the mattresses had to be reconfigured with the insert having the appropriate density to provide the necessary pressure relief to the patient. The reconfiguration of the mattress necessitated the opening of the protective outer cover of the mattress increasing the possibility of contamination of the mattress. The reconfiguration of the mattresses also involves moving the patient from the bed. Moreover, since different foam inserts were required, the inserts had to be stored when not in use.